Apparatus for treating water



Ju1y'4, 1944.A w. 1. KLEM 2,352,901 APPARATUS TREATING WATER Filed Julyl, 1940 2 Sheets-Sheet l nm VACUUM VALVE la Y# 40 Hm RELEHSEVALVL FEL fM g E l 1 Y CONTACT Ammon g i '1"' 2V 2i-2m l f 23 Hmmm 7 l I y 1'7 fg 7/fe BY WNW-MUM July 4, 1944.r w. l. KLEIN 2,352,901

I APPARATUS FOR TREATING WATER i Filed July 1. 1940 2 sheets-sheet 2mvENToR WILLIAMLKLEIN.

Patented July 41,19

- APPARATUS FOR TREATIN G WATER William' I. Klein, East Grange, N. J.,assignor to Medford Engineering Co., Medford, N. J., a corporation oi.'New Jersey Application July 1, 1940, serial No. 343,376

3 Claims.

This invention relates tomethods and apparatus for treating water,particularly for the removal of iron and acidity and has for an objectthe provision of improvements in this art.

The usual method of removing iron and acidity from .water is to aerateit as by spraying it under pressure into the open air, then filtering itthrough beds of graded gravel and sand. The water must be re-pumpedafter the aeration treatment and commonly is given a milk of limetreatment to further remove acidity. The filter beds have 'to be washedafter a certain period of y use to remove the sludge material, and greatcare has to be maintained to prevent disturbing the graded layers of`gravel and sand.

Open air aeration has a number of disadvantages. It is subject tofreezing conditions in cold weather; it Wastes much Water into thepassing air currents; it takes up contamination from the air, in somehot countries this being so great that it is impossible to use open airaeration; its efficacy varies with barometric and temperatureconditions; and it requires re-pumping of the treated water.

According to the present invention the water is aerated in animprovedmanner in a closed container under pressure. This eliminates repumping;the pressure can be accurately controlled; there is no chance ofcontamination because pre-treated and sterilized air can be employed;and the contact currents of air and water can be accurately controlledand are not subject to the variations due to gusts. and swirls of air asin the open aeration plant.

With the idea. of eliminating the disadvantages of open air aerationcertain forms of pressure aerating plants have heretofore been proposed.

The present invention in addition provides for sludge removal and acidelimination in the same apparatus at the same pressure and withoutrepumping. A considerable portion of the sludge which is produced byaeration is removed in the portion of the apparatus Where the aerationoccurs; and the remainder is taken out in a uniform b ed of sand whichis not injured for its intended purposes by being mixed during Washinmasa graded-gravel layer lter would be.

The invention also provides for complete acid removal in the same sandfilterbed which is used for sludge removal, there being used or mixedwith the sand a suitable corrective material such as marble, calcitefaspecially treated silica sand, or a specially prepared granulardolomitic material which does not settle 'out like lime and whichconsequently maintains its effect and prevents incrustatio'ns andcorrosion throughout the pipe distributing system and avoids red waterevenv at great distances from the treating plant. Moreover, the sand by-being mixed with the granular treating material has a scrubbing effecton the latter during washing to keep it clean and active.

The apparatus provides for automatic vacuum relief when the raw watersupply is cut o and the sludge-containing water is drained from theaeration contact bed which is employed.

The invention provides for washing the filtertreating bed with airvorwater or both at any desired pressure. If desired the same treatment maybe given the aeration contact bed.

In the manner in which the acid-removing material is used herein ittends to maintain uniform efcacy in all stages of use from the time thebed is freshly charged until practically all of the material has beenused up. This'is true because the smaller particles tend to rise to thetop and collect moreclosely together so as to contact the Water morethoroughly, and the particles soon assume their natural relativeposition even though the filter bed may be completely upset duringwashing. Therefore, while -the coarse particles are rather uniformlydistributed throughout the entire depth of the filter bed when firstcharged and act over a greater distance, the smaller particles becomemore closely collected near the top duringlater stages after eachsuccessive washing and act more effectively though for a shorterdistance. Finally almost' all the material may be collected near the topof the filter bed just before exhaustion but it will be in such fineparticles and so closely collected that it will still havepracticallythe same full effect as when the coarser particles Werefreshly charged.

Other features, objects and advantages of the invention will be apparentfrom vthe following Y description of an illustrative embodiment thereof,when considered in connection with the pre-y ferred form of apparatusshown in the accompanying drawingsl in which: Fig. 1 is a verticalsection, partly in elevation, *l

Fig. 4v is an enlarged partial horizontal plan.

View of parts shown at the left side of Fig. 3;- and Fig. is a verticalsection taken on the line I-l oi' Fig. 4.

Referring to the drawings, a closed tank l'is provided with atlowerfalse-bottom or grid il adapted to retain thereon a illter bed I2 ofgranular material such as sand or a dolomitic or other granular treatingmaterial or preferably a mixture of the two granular materials for apurpose which will be more fully explained hereinai'ter. This illter bedmay. for example. be 48 inches deep for a tank which is, say, 9 feet indiameter.-

At some distance above the illter bed there is located anotherfalse-bottom or grid il such as a wood slatting adapted to retainthereon a bed I4 of a coarser broken material, preferably a porousmaterial such as lava or-slag. This portion of the apparatus will bereferred to as the contact aerator.l

2 2,859,901 y y l drained tol cause it te rush down'uirouzh the bed iland remove sludge, the opening oi-valve Il with a distributor head withopenings around the f side to spread the water evenly and smoothlyacross the entire space inthe tank. Preferably thelnlet openings arebelow the water level in the tank. as illustrated. The water inlet pipeil may also serve at times as a wash water` drain pipe when the aerationbed is being hack-washed.

For this purpose the raw water supply pipe 2B which connects with theraw water inlet pipe i0 is provided with a cut-ot! valve :2| and theaerator waste pipe 2! which also connects with the raw water inlet pipeI0 is provided with a cut-ot valve 23. The wash waste pipe I 'I is pro-yvidedwith a cut-oil valve 24. Both the wash waste pipe I 'I and theaerator waste pipe 22 empty A' treated water outlet pipe al leads fromthe collector space i! and this pipe is providedwith a cut-oi! valve Il.Opening into the same space is a wash water inlet pipe Il provided witha cutoi! valve 8l. Also opening into the space il is an air wash inletpipe il openinginto spreaders Ila, and provided with a cut-oil valve b4as shownin Fig. 3. A drain pipe Il leads from the bottom of the space I!to the waste sump 2l.

The drain pipe is provided with a cut-ci! valve 38.

vIn the top-oi the tank there is placed 4ari air vacuum relie! valve 3loi' suilicient size to permit ,rapid draining o! water from the tank.There is also an'air release valve Il which may be controlled by a iloatIl. When the air pressure becomes too great it i'orces down the-.waterlevel. indicated by I2, and permits air' to escape until the pressure isequaliaed at the proper point.

' The air release valve 4I has only a small openwould be toovsmall topermit air at atmospheric pressure to enter rapidly in sumcient amount-to avoid a partial-vacuum which would retard the draining of the water.*Wherefore the vrelatively large relief pipe and relief valve I! areprovided to permit air at atmospheric pressure to enter as i'ast as thewater can ilow out.

In' normal operation for treating water, theraw water inlet valve 2| isopen, the aerator waste valve 23 closed, the wash waste'valve 24 closed,the treated water outlet valve Il open, the wash water inlet valve 33closed, the drain valve 30 closed. the valve b of the air wash supplypipe Il closed, and the valve 23a of the aeration pipe 2l open.

Raw water will then issue from the distributor head of the raw waterinlet pipe I8 so as to be spread evenly across the tankabove the lavabed or contact aerator il and flows down uniformly through the lava bedwhere it meets the uniformly distributed air flowing upward from the airspreader 21 and forms, an emulsion therewith. At the start the valve 40is fully open and air escapes i'reely from the top of the tank so thatthe tank air pressure is only slightly above atmospheric pressure,though supplied by pipe 28 at a high pressure and in constant inflow.Howf- 1 ever, as the water level rises` it will raise the iloat Il and-restrict the passage at valve Il until a balance is established betweenwater and air pressures.

l'ior the aeration bed there is used cracked and graded honeycomb lavahaving a specific gravity sumcient to overcome iloating and maintain aiixed position. This works better after it has been in use for sometime, apparently after becoming coated thorou'hly with sludge. appearsto be some est-lytic action over the extremely large contact areapresented in the honeycomb lava and other highly porous material oi thistype, but this action need not be investigated, it being sumcient toknow that the desired action does occur. This porous and dividedmaterial breaks up the downilowing water into a great number oi.' verysmall streams that thoroughly contact and mix with globules oiasing,fiand this is as large as yrequired because the entrapped airwhich it permits to escape during aeration is under relativelyhishpressure. But when the water in the tank is t0 be suddenly cending airto form the desired emulsion. This causes the oxidation oi iron andmanganese in the water; converts the iron content from a condition orsolution to a state oi' suspension; and at the same time causes thegases in the water to be released and carried oi! by the ascending air.

The lava bed also acts as a sedimentation basin to remove and store' aconsiderable portion ci the oxidized iron removed from the water. 'Ihismay' amount to 40 or 50% of that removed.

The aeration may .be accomplished under any working pressure that may berequired and under any conditions of the water suppl! System. Theupilowing air accomplishes its purpose without l causing any stoppage orretardation ci the now of water. Very accurate control of the pressures,

1 tion can be accomplished without leavingexcessive amounts of oxygen inthe watergthus leaving it in a less aggressive condition.

The used air with entrained gases accumulates There assaooi 3 I grainsof dolomitic material being'approximately' ,intheairspacelinthetopofthetankand Vof the same size and specific gravity as the sandwhen the predetermined pressure is exceeded escapes through the airrelease valve III.

In operation, a closely maintained working balance is achieved whereinthe oat II remains substantially at a constant position to release airthrough the valve t continuously at the rate at which it enters throughthe inlet pipe 28. The iloat 4I is disposed in a position where it willnot be materially aiected by any yturbulence which may be caused by theflow of water or air.

For clarity of illustration it is shown at one side of 'the end of waterinlet pipe I9, but in practice A for very smooth operation it may beplaced directly above the cover plate of the pipe, the quiet body ofwater above this plate being of suflicient depth to permit the requiredmovements of the oat.

grains.

The uniformity of grain size in the lter obtains complete removal ofdirt and sludge from A 'the particles by friction with the sand grains.

More violent contact occurs between the grains by using slower watervelocity combined with air than by high rate of ilow of wash wateralone.

`During the operation of washing, the particles ol' corrective material,such as magnesite, marble or zeolite, become reduced in size and tend toform a chemically active layer on top of the filter bed. 'I'hus iscombined a chemical filter withva physical lter of coarser particlesmixed l with the sand bedv below. But as the grains of The linkagethrough which the neat u aetuates the closure member or plug 40a of thevalve 40 is very similar te that of float valves used for many otherpurposes. Here the float 4I is secured on an arm IIa pivoted at llb to afixed support 4Ic carried by the removable cap Ilia. The valve plug 40ais secured to a valve arm 4Gb which 4is pivoted to a support on the capIlia' at 40e. A link 40d is pivotally connected to the outer end of thevalve arm 40h and to an intermediate part of the float larm lla.

The filter bed I2 performs two functions. It removes most of theoxidized iron and manganese which was not deposited in the aeration fbed Il and it brings the water to a state of carthe apparatus istherefore perfectly clear and will not incrust or corrode pipes, eventhose made l ofiron, for any usual distances from the treating plant.Red water, which is common with water obtained from other treatments, istherefore avoided by this treatment. i

The entire area and depth of the lter bed is effectively utilized andthis is realized because the entire .bed is able to rid itself of allthe suspended oxide (of iron, manganese, etc.) taken from the water.This is done in such manner that the filtering medium is maintained in aclean, uncoated and active condition. The bed does not employ 4theso-called standard underdrain comprisingmanifolds vand laterals and'layers of graded gravel, but instead it employs ing application ofFrederick Tschirner, Serial No.

336,007 filed May 18, I1940. The present inven-` tion provides animproved method of using this dolomitic material to obtain its fulladvantages. It is intimately mixed throughout the bed of sand;consequently when the bed is back-washed the hard particles of sand havean abrasive action on the dolomitel grains, to free them from sludge andleave their outer surfaces clean and active. A similar, though lessrapid, abrasive cleaning action is realized when the dolomitic materialis used alone, the grains in agitation rubbing against each other toeffect removal oi softer outer portions or accretions.

When the bed is freshly charged` with dolomitic material there is auniform homogeneous mixture throughout the depth of the bed, the

dolomitic material become smaller they seek a higher level, particularlyduring the back-washing and finally may collect near the top just beforeexhaustion. y

Thus the filter, surface becomes charged with the ner particles of thecorrective material to `form a chemically active layer on top of thephysical filter below and thus combines the properties of\ a chemicalfilter with a physical lter and obtains both absorptive action andstraining action. Consequently the bed is very effective untilpractically completely exhausted.

When the contact aerator or lava bed is to be cleaned the treated wateroutlet valve 3| and the 'raw water inlet valve 2| are closed and thewash waste valve 24 is opened. The air to pipe 28 is also cut olf. Thewater in the upper portion of the tank then drains rapidly out the washwaste pipe II, the vacuum relief valve 39 opening wide to allow therapid inflow of a large volume of air to displacethe water. This drawsmost of `the oxide sludge out of the lava bed. For further washing, theraw water valve 2l may be opened suillciently to cause a flow of waterdown through the bed of lava to the Wash Waste pipe. For additionalcleaning, a blast of air fromthe pipe 28 may be released into the bedwhen there is little or no Water present therein.

The lava bed may be back-washed with air or `water or'both if desired.For this purpose- (proceeding from the condition last stated above) thewash waste valve 24 is closed and the aerator and out through pipe I9 tothe sump 25. For

back-washing with air, either alone or in conjunction with the waterback-wash, the valve to air inlet pipe 28 is opened and the air flowsupward through the' bed and out the valve 40.

The release valve 40 is so designed that the air and entrained gaseswill be released with air supplied at pressures higher than theoperating water pressure without interfering with the free flow of waterthroughthe system. 'Ihis system may be operated with the aeration andlava bed in a separate unit ahead of one or more filter units orcombined with a filter unit below the aeration chamber as hereindescribed. Then the wash Water inlet valve 33 is opened and also, if

- 33 is closed. This gives an air wash. In this action the illter bed I2is also back-washed.

The filter bed alone may now be back-washed i by closing the aeratorwaste pipe 23 and opening the wash waste valve 24.

When oxide sludse is to be washed downward from the lter bed the drainvalve Il is opened, all valves other than the vacuum valve 30 beingmaybe opened sumciently to supply adequate wash water through the nlterbed.

Suitable ports with closures are provided in the tank for removing oldmaterial and supplying new material. Practically the only new materialto be supplied, except at very long intervals, of course, is thedolomitic or other corrective material.

The illter bed rests directly upon a falsebottom lter under-drain plate,and thisA drain plate separates the filter bed above from the clearwater chamber below, access both downward, during normaloperations, andupward, during back-washing operations, being provided by ports 45 inthe illter under-drain plate which are covered with indestructible andnon-clogging steel wire mesh'l. These details are shown in Figs. 3, 4and 5. y

'I'he clear water basin below the false-bottom illter under-'drain plateis provided with an air distribution grid which permits the applicationof compressed airand its utilization asl an auxiliary nlter bed washingand cleansing means.

` The air outlet openings are placed in the sides or bottomand not inthe top of the grid to avoid too pronounced a`blasting action but ratheran evenly diifused flow of air. The illter bed is not injured byagitation in back-washing but a violent agitation such as might carrythe small granular material out the waste openings is avoided.

The air outlet openings inthe upper air grid 21 are preferably directedupward to, forcibly blast the downilowing water in the lava bed, the

material of the bed being suiiiciently large andv heavy to permit thisand the downfiowing water tending to counteract the effect of theupilowing air. n.

The system is not only eil'ective'in maintaining a clean filter unit butit accomplishes this'V with a material saving in the volume of washwater or waste required for this purpose as against the so-calledstandard system,` which iron by sedimentation, all underpressure andlwithout pumpage. This is much more satisfactory than atmosphericaeration and sedimentation and eliminates the chance of incidental con-vtamination from free air exposure, eliminates waste of water fromexposed air currents, and

eliminates atmospheric troubles due to freezins. It eliminatesallvariations due to -changing barometric conditions that hindersuccessful aerationv of water,.and maintains a definite and properdegree of oxygen content which is always under control, a feature whichcannot be controlled by atmospheric aeration.

In thefenumerated and in other' respects the apparatus and method have.proved advantageous for the desired purposes'.

While one embodiment of the invention hasl been described. it is to beunderstood ithat the invention may havevarious-embodiments withinclosed, except that the raw water inlet valve 2| y the limits of theprior' art and the scope ofthe subioined claims.

I claim:

1. Apparatus for treating water, comprising in combination, a closedpressure vessel, an aeration bed of coarse porous granular'rnaterlal ln'said vessel disposed at a distance below the top, a valve-controlledraw water supply including a 4 head above the aeration bed for spreadingwater the aeration bed causing a sludge separation' l from the water,some of which sludge deposits in the aeration bed, a lter bed of finegranular material in said vessel disposed at a distance above the bottomto leave a clear water space therebelow, the illter bed also beingspaced at a' distance below said aeration bed, a valve-controlled washwaste pipe opening into the open space between beds, a valve-controlledwash 4water inlet opening into the bottom of the tank, l

and valve-controlled means for supplying air under pressure uniformlyacrossand below the bottom of said filter bed.

2. Apparatus for treating water to remove iron and acidity, comprisingin combination, a closed pressure tank, apwood slat gridv near the topthereof supporting a bed of coarse lava to break up the flow of waterand receive a. deposit of sludge from iron removal, a metal grid nearthe 'bottom of said tank and including spaced ports covered with finescreen wire and supporting a filter bed of sand mixed with a ilnegranular correcting material, there being left a clear water space inthe bottom, a drainspace in the center, and an airspace in the top ofthe tank, a pipe leading into the top of the tank and provided withvalved pipe connections for supplying raw water to the tank or fordraining back-wash water from the tank, the water level in normaloperation being' maintained above the lava bed, a valve wash waste pipeopening into the center drain space, a pipe opening into the clearwater' pressure tank,`.a grid in the upper part of theV tank supportinga bed of coarse granular material to break up the downfiowing water andretain a deposit of sludge from iron removaL'a grid near the bottomoflthe tank supporting a filter bed ofl line granular material, therebeing left a clear water space below thenlter bed in the bottom of thetank, a drain spaceand a valved wash waste pipe in the center of thetank between the upper grid and' the -nlter bed, an` open space forwater and air in the top of the tank, pipe vand valve meansfor'supplying raw water to or draining backwash Awai-.er from the top ofthetank selectively, pipe `and valve means :lor withdrawing treatedwater from or supplying wash water to the ,open space in the bottom ofthe tank, 'pipe and valve means for supplying air under the upper gridto ilow upward through a body of water which submerges the upper .bedand stands at a level thereabove and below the air space in the top ofthe tnk, pipe and valve ymeans for supplying air beneath the lower grid,A:at oat control valve for releasing air from the top of the tank, ands, vacuum relief valve for rapidly admitting air to the top of the tankto permit rapid withdrawal of water.

WIILIAMLKLEIN.

